askquestion

2 years ago

An ice cream parlor sell ice creams with three different flavors: blue- berry, chocolates, and vanilla. How many ways are there to choose a dozen ice creams with at most six vanilla ice creams? (Note: one dozen consists of twelve ice creams).

I would suggest this method:
How many ways are there with exactly 0 vanilla
How many ways are there with exactly 1 vanilla
How many ways are there with exactly 2 vanilla
How many ways are there with exactly 3 vanilla
...
How many ways are there with exactly 6 vanilla
Then I would add them up.